Method of printing



Nov. 26, 1929.. F. M. ALLEN METHOD OF PRINTING Filed Dec. '7, 1927INVENTOR FRANK M. ALLEN M ML? A TTORNEY Patented Nov. 26, 1929 UNITED STTES PATENT OF CE rmmzm. ALLEN, or CLAYMONT,'DELAWARE, Assrenoa TOOONGOLEUM-NAIRN, 1110., 'A coaronerron or NEW YORK METHOD OF PRINTINGApplication filed December 7, 1927. Serial No. 288,259.

The invention relates to printing machines, and more particularly toprinting machines of the bed-and-platen type as described and claimed inthe Waldron Patent No. 1,145,821.

Printing. machines of the type referred to, comprise, in general, a setof platens carrying printing blocks, which are adapted to bereciprocated by suitable mechanism to impress a design upon a basematerial as it is conveyed step by step through the machine over the bedand work-suppo'rtin members. In the present-day. machines, t ework-supporting members consist of flat pads each having a Wood backingand a top of wool felt of uni- 1 form thickness, covered with oilclothor similar material. The pads are suitably cradled in'the framework ofthe print machine beneath the set of platens, the'felt faces beingadapted to provideflat, compressible worksupporting surfaces, againstwhich the print blocks may abut without injury to their printingsurfaces, Intermediate the worksupporting members or pads, and in aplane therewith, are wood or steel plates, forming with said pads acontinuous fiat bed over which the work is conveyed. As the flat printblock is brought into association with the Work supported by the flatfelt pad for the purpose of depositing paint thereon, or for flatteningor mashing the paint previously deposited, a strong cohesive relation isset up between the print block and the work, whereby the raising of theprint block from the printed surface is opposed with great resitance. Ii-consequence, the work is slightly raised from the work-supportingmember by the suction of the block, until the opposing forces break thebond and the work is suddenly torn from the block. Frequently, this 0results in spattering the paint and in many instances the paint israised in pits and points so that the work has an uneven and roughappearance. With relatively slow reciprocation of the platens andblocks, this defect, 5 while apparent, is not serious, but as the speedthe framework of a bed-and-platen type slidably journalled in thebearings 7, 7 and of operation is increased, the defect becomes mostserious,- and functions as one of the chief factors in limiting theprinting capacity of the machine. I

- The chief object of my invention is the provision of a novel methodfor'reciprocatmg the platens carryin the print blocks,

whereby the defects outlined above are substantially eliminated and'anincreased speed of operation is obtained. p In the accompanying drawing,forming a part of this specification: Figure 1 represents a sectionalelevation of the conventional bed-and-platen type printing machine,adapted to operate in accordance with my invention.

Figure 2 is a graphical representation of the novel mode ofreciprocationof the plat ens. I 1

Referring to the drawings, '1 designates printing machine. Cradled inthe framework or the work-supporting members constituting the bed 2 overwhich the work is conveyed step by step by the endless pick belts 3.Mounted over the work-su porting members are platens 4 carrying t eprint.- blocks 5; The platens are supported ateach end by the verticalmembers, 6, 6", which are are adapted-to be reciproca'ted by means of Ithe cams 8, 8 and the cam followers 9, 9'. The cams8, 8 are keyed to thedriving shaft 10, which is suitably journalled in the frame- Work 1.

In the construction and operation of the present-day bed-and-platen typemachines, the cams 8, ,8 are symmetrically designed and are sopositioned upon the shaft 10 as to cause the cam followers 9, 9 tomovesimultaneously and co-extensively. Thus, the platens 4;. and blocks 5,when once adjusted to the-position parallel to the print bed 2, remainin such parallel relation throughout the complete cycle of verticalreciprocation? In oont'radistinction to this mode of operation, thepresent invention contemplates that the platens and blocks shall move inparallel alignment with the print bed throughout a portion only of thecycle of operation, and during the remaining portion of the cycle shallassume an oblique alignment for the purposes hereinafter explained. Moreparticu arly, the print block is first positioned in parallel alignmentwith the bed at substantially the full height of its'vertical movement.While thus positioned, the paint carriage (not shown) passestherebeneath in the usual manner to deposit the coloring matter upon theprinting surface of the block. The platen or ,block then movesvertically downward into printing position, while constantly maintainingthe parallel alignment. At the end of the printing period, one end ofthe platen or block is raised a substantial amount, while the oppositeend is still maintained in printing position. By this movement, theparallel alignment of the print block and bed is de- 1 stroyed and theblock is separated from the imprinted surface by line-contactdisengagement. Both ends of the block are then moved vertically upward,the lower end being raised more rapidly, whereby the block and platenhaving reached their full upward vertical movement, are restored againto parallel ali nment.-

s a simple and preferred manner of carrying out my invention, Iconstruct the platen cams 8, 8 so that when the cams are properlypositioned upon the shaft 10 to cause parallel alignment of the bed andplatens during the vertical downward movement and printing period, thelifting sector of cam 8 becomes effective prior to the lifting sector ofcam 8. In this manner, one end of the platen is raised the desiredamount, while It'h opposite end remains in printing position. Theremaining portion of the lifting sector of the cams will be of suchdesign as to cause the platen to return to parallelalignment with thebed before or upon reaching its full vertical upward movement.

In Figure 2, I have illustrated graphically the movement of the platenor block throughout the cycle of operation, curves A and B defining themovement of-the ends of the block indicated by a and b respectively.From 7' to- 8, both ends a and b of the block move downwardsimultaneously and co-extensively as indicated by the coincidence ofcurves A and B. During the period 8 to t,

l the print block is in printing position and in parallel alignment withthe print bed. At t,the end of the block a commences its upward verticalmovement as indicated by the curve A, while the end of the block 6remains in printing position as indicated by the portion t to u of thecurve B. This angular movement ofthe block causes the same to separatefrom the imprinted surface by line-contact disengagement incontradistinction to the plane-cleavage disengagement as in theheretofore known manner of operation. At the points and u, the printblock has assumed an ob ique alignment substantially as shown in thedotted lines in Figure 1. In most cases, this vertical movement of oneend of the print block will be about 1 for standardblocks of 7 2"length. With longer blocks i. e., wider print machines, the movement maybe somewhat greater. 'In general, however, it may be stated that forbed-andplaten type print machines of the Waldron type, the safepermissible angle between the block and bed, is about one degree. Thisangle is, however, ample for securing the advantages of line-contactdisengagement and also permits the highly desirable rigid constructionof the print machine to be maintained. The block having beensubstantially separated from the imprinted surface, both ends thereofthen move upward from the points p and u as indicated by the independentcurves Aand B, until the block returns to parallel alignment asindicated at '22. Such parallel alignment continues until the block hasagain reached the point t in the subsequent cycle of operation.

By means of my invention, the print block is brought into printingposition in parallel alignment with the bed, thereby providing a,uniform print upon the work. As the block commences its upward movementsub sequent to the printing period, however, the parallel alignment isdestroyed, thereby causing the work to separate from the printingsurface, commencing at 'one end of the block, smoothly and easily byline-contact disengagement. This feature of line-contact disengagement,similar to the peeling action in rotary printing machines, entirelyavoids the sudden plane-cleavage of the bond between the print block andthe work. Furthermore, such operation substantially eliminates allspattering occurring from the sudden separation of the print block andwork, and avoids the formation of pits and points of paint. Of chiefimportance, however, is the fact that-by the application of theprinciple of my invention, I am able to obtain a' considerably increasedspeed of reciprocation of the print blocks, which results in increasedcapacity of the print machine, and at the same time to produce printswhich have a uniform and smooth finish.

I claim: I

1. In the operation of a bed-and-platen type printing machine of thetype described, the steps of first effecting plane-contact engagement ofthe print block and surface to be printed, and finally effectingline-contact disengagement of the print block and imprinted surface saiddisengagement com mencing at the one end of the print block andextending to the opposite end of the print block.

2. In the operation of a bed-and-platen type printing machine of thetype described maintaining parallel alignment of 'block and bed duringthe vertical downward movement of the platen and the printing period,destroying the parallel alignment just subsequent to the printing periodto cause linecontact disengagement of the block, and finally restoringthe parallel alignment before the completion of the upward verticalmovement of the platen. In testimony whereof, I aifix my signature.

FRANK M. ALLEN.

